Think you need to use lighting equipment to get a bright interior? Think again! This tour is shot by a company based in Seattle called Vista Estate. Vista Estate's approach is to shoot with no lighting equipment. This is one of their sample tours that shows what you can do without any extra lighting equipment, just a tripod and post processing work.
I can't tell you exactly what techniques they are using. It's obviously some derivative of HDR processing or blending. Most of the images are well done HDR because they don't have the things tell tale HDR look. I'd love to reverse engineer exactly what techniques they are using.
Also the iFlyer tour format that Vista Estate Imaging is using is note worthy. It has a clean and elegant design and is the only tour I've seen that adapts (re-sizes the window) to vertical format images. Unfortunately, the only way to use this tour format is to have Vista Estate do you photos. Vicaso is the name of the company that does the web development for Vista Estate Imaging.
One of the interesting aspects of doing this blog has been seeing the different approaches photographers have to make interiors bright. Everyone that gets into this business seems to have a natural inclination to either use some form of lighting equipment or to do more or even all of the job in post processing. Scott Hargis, Thomas Grubba and M. James Northen are contributors to the PFRE flickr group that are notable practitioners lighting equipment approach while David Palermo and Vista Estate are practitioners of no or minimal lighting equipment approach.